Traditionally, pan and mold releases used in the food industry, especially the baking industry, have been composed of fat or oils (animal or vegetable) with, in most cases in recent years, certain additives such as lecithin, silica, and cereal flour used to improve the release.
In the production of pan bread (so-called hearth breads are not baked in pans) and cakes, the pans used are usually coated when manufactured with a silicon glaze to aid in the release of the baked food. After some use, the pans are removed from the bakery to be commercially cleaned and reglazed, at considerable cost, due to the wearing away of the glaze and the buildup of residue.
It has been found that coating the pans with a film of fat or oil prior to each use both improves release and extends the life of the glaze when used. The inclusion of certain additives, such as lecithin, a naturally occurring surfactant, improves the release action of the fat or oil coating.
Similar type coatings or lubricants are used in the food industry in general. They are used to reduce sticking to conveyor belts, to improve the cutting actions and prevent sticking of cutting blades used to cut confectionery pieces, to lubricate belts and moving parts used to process foods, to coat packaging materials to prevent sticking and many other applications. Such releases differ basically in viscosity.
The coating may be applied manually, but, in large bakeries, is usually sprayed on the pans in liquid form using especially designed equipment that automatically sprays each pan with the proper amount of release, applied to the proper area of the pans.
Unfortunately, many of the fats, oils and other additives contain impurities such as rosins or are polymerized by heat resulting in the build-up on the pan or other equipment of carbonaceous encrustation, composed of rosins, polymerized oils and entrapped burned residues of the baked food.
Bread, because of its relatively low sugar and shortening content, is more easily released from the pan than is chemically leavened cake or yeast-raised sweet goods of high sugar and fat content. For this reason, the release used for bread and rolls may be simply a fat or an oil, with or without lecithin. With cake, which tends to be sticky, additional additives such as silica or cereal flours and/or starches may be included to improve release.
Strouss, in U.S. Pat. No. 4,339,465 issued Jul. 13, 1982 teaches a dispersion of a liquid emulsifier in water with or without a maximum of 4% "unbleached liquid soya lecithin", preferably 2% with a minimum of 80% water. Strouss adds such lecithin as an optional ingredient only to increase the adhesion properties of the composition of matter. I have found that unbleached soya lecithin, while usable if emulsifiable, is undesirable since it imparts a dark color to the emulsion and possesses an undesirable beany odor. I can obtain the increased viscosity and resulting improved adhesion by adding silica, especially fumed silica, and by reducing the water content of the aqueous phase. I can also obtain greater viscosity by adding cereal products such as but not limited to finely milled corn flour or starches to the aqueous phase. Gums such as but not limited to alginate, cellulose, carrageenin and guar will also increase the viscosity of the aqueous phase. The ideal pan release would be economical, have a low viscosity so as to be applied in a very thin film, would not smoke or give off foul odors in the oven or elsewhere, would not impart off flavors or odors to the food product, would provide good release properties in that little, if any, product would stick in the mold or pans, would extend the glaze life of the mold and pans and would not contribute to the buildup of carbonaceous matter on the mold or pan.
Ideally, the liquid release would obtain its fluidity from a solvent such as water. Water is about the lowest cost and least troublesome solvent available. It is nontoxic, odor and flavor free, is not flammable and does not smoke when exposed to high heat, gives off no pollutants and contains no rosins or polymerizable material which might deposit on the pans.
Japanese Patent No. 141 842 issued to Takahashi discloses the formation of a release for use in aerosol containers under pressure from a gas such as nitrogen. Takahashi teaches the formation of an oil-in-water type emulsion with up to 5% lecithin of unknown HLB, an edible oil content of 20-45%, an emulsifier such as sorbitan or polyglyceryl esters and water at 45 to 78.5%. Takahashi requires very expensive emulsifiers to form the emulsion. In addition, the solids content of Takahashi is very low.
The primary release agents, such as fats and oils and conventional lecithin are not soluble in water, thus, would have to be dissolved in expensive and unsafe solvents such as alcohol or hexane. Conventional lecithin has an H.L.B. of 2 to 4.
Hydrophilic lecithin would have an H.L.B. value of greater than that of commercial lecithin.